Surgical microscope systems often comprise a surgical microscope, a retaining system to which the surgical microscope is fastened, and a stand base, which forms the base of this retaining system. Since surgical microscopes are available in various levels of equipment, the weight of the surgical microscope changes depending on the level of equipment. A weight change of the surgical microscope has effects on the retaining system and the stand base of the retaining system. In order to avoid a tilting of the stand base in any case, this is therefore to be formed so as to be as heavy as possible. An increase of the weight of the surgical microscope on the one hand may therefore be associated on the other hand with a necessary increase of the weight for the stand base.
A microscope stand with a multi-part foot with weights which can be mounted in a cavity or on an initially open cavity in the stand base body without rotating the stand base body is known from U.S. Pat. No. 6,305,659.
Carl Zeiss Meditec AG, under the name “S5”, offers a stand base on which the invention is based. This stand base includes a hollow stand base main body, which can be equipped from the underside with weights. These weights are secured by retaining elements in the stand base main body.
Although on the one hand a high stability is necessary, which is achieved by a high weight of the stand base, there is on the other hand also the desire, however, to design the surgical microscope system in such a way that it can be moved between different locations. For this reason, it is also known to equip the stand base with castors in order to enable a change in position of the entire surgical microscope system by moving the stand base on the castors. However, an unnecessary increase of the weight of the stand base significantly impairs the ability to move the surgical microscope system to another location. It is therefore usual in practice to equip the stand base with the minimum weight necessary in order to ensure on the one hand a secure footing of the surgical microscope system and on the other hand to enable maximum movement comfort when moving the system on the castors of the stand base.
In order to accommodate the wide range of various equipment variants of a surgical microscope and the associated differences in weight, there is thus a need to be able to equip the associated stand base in a number of different weight levels. Since the weight differences of the various levels of development of a surgical microscope may be considerable, the conventional method of fitting weights in a stand base body may no longer be sufficient to cover the necessary large weight range reliably and cost-effectively.
In addition to the requirement of a stand base with variable weight, there is a demand for the avoidance of the risk of foot injuries. The standard DIN EN 60601-1 3ed is incorporated herein by reference and demands protection in order to prevent injuries to a user's feet. For this purpose, the distance between the underside of the stand base and the floor or ground must be either greater than 12 cm or smaller than 3.5 cm. This safety requirement is referred to as underrun protection.